The present invention relates to an automatic flowable material dispensing apparatus which in a preferred embodiment relates to an apparatus for dispensing ink to a plotter.
Plotters require a steady and constant supply of ink for operation. An undersupply or oversupply of ink may render plotter operation unacceptable. An oversupply of ink is undesirable because the excess ink may cause blots on the plot or cause the plot to be inaccurate or illegible. An undersupply of ink is undesirable because without a sufficient ink supply, portions or all of a plot may be lost.
The use of disposable pen cartridges as the ink supply source is problematic because a plotter so equipped must be continuously monitored to ensure that the pen cartridge has not run out of ink. A worker is required to monitor the plotter and to replace the disposable pen cartridge when depleted. If a plotter is to be used over a long time when constant monitoring is not feasible, a new disposable pen cartridge must be installed as a precaution against a partially depleted cartridge being fully depleted at some point during the long time period. As the partially depleted cartridge is usually discarded, this method of operation is economically disadvantageous.
Pressurized ink supply systems are also known. However, such a system results in an uneven flow of ink to the plotter pen, thereby producing unacceptable plots. Such a pressurized ink supply system may render the plotter pen inoperable and may even cause the plotter pen to explode.